Continuing the Fall of Cadia will bring Lord Guilliman, and the campaign goes global for the summer. Here is the latest whispers.
Good Sources, please remember that these are rumors.
via anonymous sources on Faeit 212
1. Fall of Cadia is the prelude to what will be a global campaign over the summer - look for big build up after Tzeentch and then the campaign should start in ~4 months. It sounds like it's going to be global, he wasn't sure what format it would take (e.g., if it would be global with implications like the last black crusade campaign)
2. Lord Guilliman...will be making his arrival (return?) to the 40k sometime before that campaign kicks off. Didn't sound like there would be more primarchs than Guilliman and Magnus heading in but 4 months is a long time.